Full Idea
There exists an eternal unmoved substance separate from sensible things. It can have no magnitude, and is without parts and indivisible. As the source of movement for infinite time, it must itself be infinite.
Gist of Idea
There must a source of movement which is eternal, indivisible and without magnitude
Source
Aristotle (Metaphysics [c.324 BCE], 1073a05)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.375